/* AbstractSelectionKey.java --
   Copyright (C) 2002, 2003, 2004  Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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any later version.

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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

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along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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package java.nio.channels.spi;

import java.nio.channels.SelectionKey;


/**
 * @since 1.4
 */
public abstract class AbstractSelectionKey extends SelectionKey
{
  private boolean cancelled;

  /**
   * Initializes the key.
   */
  protected AbstractSelectionKey()
  {
  }

  /**
   * Cancels this key.
   */
  public final void cancel()
  {
    if (isValid())
      {
	((AbstractSelector) selector()).cancelKey(this);
	cancelled = true;
      }
  }

  /**
   * Tells whether this key is valid or not.
   *
   * @return true if this key is valid, false otherwise
   */
  public final boolean isValid()
  {
    return ! cancelled;
  }
}